[luckylion]

I'd imagine the peer-pressure to be very large. In the world of private torrent trackers, you have a similar setup. Each tracker is independent in general, but there is the cabal, a group of elite trackers that dominate their vertical in pretty much all metrics, and are connected via staff knowing each other. You misbehave on one cabal-tracker bad enough, you're gone from all of them.

Lower tier trackers will often adapt the cabal's decisions for various reasons. You end up with a situation where one staff member making a decision can end your membership on a dozen sites.

In the torrent world, it's pretty open. I expect the same to be the case on the fediverse, even if it's not publicly communicated. I'm sure server admins do communicate with each other in non-public forms.